572 ALSTON, LAWRENCE, BAYNE, AND CAMPBELL 



samplers were placed at stations I and IX in each of the three 

 channels and allowed to collect organisms. Samples were obtained at 

 monthly intervals throughout the study period. 



Subsamples were often taken to estimate the number of 

 organisms in each sample, and all organisms were keyed to the lowest 

 taxa possible within the limitations of time and available expertise. 



Diversity Indexes 



Weber (1973) recommended the Shannon— Weaver function to 

 achieve greater uniformity of diversity (d) calculations. For 

 simplified calculations, the machine formula presented by Lloyd, 

 Zar, and Karr (1968) was used: 



d = §(NlogN-2nilogni) (1) 



In this formula C = 3.3219 (to convert base 10 log to base 2), N is 

 the total number of individuals, and n[ is the total number of 

 individuals in the i^^^ species. 



RESULTS 



Channel Habitat 



The highest average weekly water temperatures in channel 1 in 

 1975 and 1976 were 30.4 and 30.8° C, respectively, and in channel 3, 

 34 and 35.5°C, respectively. The highest average weekly 

 temperatures of the unheated and heated portions of channel 2 were 

 between those given for channels 1 and 3. Throughout the study 

 period the temperature differential between channels 1 and 3 ranged 

 from 3 to 10°C. The highest average daily water temperature for 

 channel 3 was 36.7° C on Aug. 1. 1976. 



Water-quality data indicated that most of the parameters 

 measured were similar. Channel 1 had the greatest turbidity and 

 suspended-matter concentration. Dissolved oxygen concentration 

 was never less than 3.7 ppm in any channel. Complete listings of the 

 water-quality data are given in the Alabama Power Company's final 

 report (Lawrence and Bayne, 1977). 



The channels had no macrophytes but did have both attached 

 and unattached algae populations as enumerated by Bright (1977). 

 Fish populations in the channels, which were stocked as closely as 

 possible to the natural fish populations in the Black Warrior River, 

 are listed by Turner, Lav^ence, and Bayne (in press). 



